Device for surveying thread breakage, especially for automatic connecting devices in spinning machines

ABSTRACT

A device for surveying thread breakage in spinning machines, consisting of a cyclically moved carriage which carries a first sensing device by means of which the movement of the traveller on the ring is sensed and a second sensing device by means of which the position of the first sensing device with respect to the rings of the spinning machine is sensed, and a switching device which is controlled by said second sensing device and which activates said first sensing device during each passage past the ring or the traveller respectively of a spinning station. If the signal from the rotating traveller is absent due to thread breakage, this will induce stopping of the carriage and start of a thread connecting device mounted on the carriage.

United States Patent 1 1 Vignon Oct. 14, 1975 [75] Inventor:

[73] Assignee: Heberlien Hespano SA,

Vernier-Geneva, Switzerland 22 Filed: Jan. 4, 1974 21 Appl. No.: 430,797

Louis Vignon, Geneva, Switzerland [30] Foreign Application Priority Data Jan. 4, 1973 Switzerland 58/73 [52] US. Cl. 57/34 R; 57/81 [51] Int. Cl. D01H 13/16; DOlH 15/00 [58] Field of Search 57/34 R, 52, 53, 54, 81,

[56] References Cited UNITED STATES PATENTS 2,930,179 3/1960 Bailey 57/81 X 3,102,378 9/1963 Walker, Jr. 57/81 3,672,143 6/1972 Whitney 57/53 3,751,893 8/1973 Goodhue et al. 57/34 R Primary Examiner-John Petrakes Attorney, Agent, or FirmLarson, Taylor & Hinds [57] ABSTRAP CT A device for surveying thread breakage in spinning machines, consisting of a cyclically moved carriage which carries a first sensing device by means of which the movement of the traveller on the ring is sensed and a second sensing device by means of which the position of the first sensing device with respect to the rings of the spinning machine is sensed, and a switching device which is controlled by said second sensing device and which activates said first sensing device during each passage past the ring or the traveller respectively of a spinning station. 1f the signal from the rotating traveller is absent due to thread breakage, this will induce stopping of the carriage and start of a thread connecting device mounted on the carriage.

7 Claims, 5 Drawing Figures H V V k/ 10 10 10' US Patent Oct. 14, 1975 Sheet 1 of2 3,911,656

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Fig. 5

DEVICE FOR SURVEYING THREAD BREAKAGE, ESPECIALLY FOR AUTOMATIC CONNECTING DEVICES IN SPINNING MACHINES The present invention relates to a device for surveying thread breakage, especially for automatic yarn connecting devices on spinning machines, which surveying device is moved cyclically along the individual spinning stations on a carriage and which is stopped by actuation of a stopping device.

For determining thread breakages, various mechanical and electro-optical devices are known and used. Whereas the mechanical devices, which are in most cases equipped with sensing levers, are subject to fault or breakdown and can only be used at low advance speed of the yarn twisting connecting device, a general disadvantage of the electro-optical systems consists in that the sensing of the thin filaments which are moved to and fro is only possible with surveying devices constructed in a highly sophisticated manner. In this case especially, the positioning of the surveying device in the position in which the presence or absence of a signal permits a conclusion concerning thread breakage causes difficulties.

It is also known already to provide on spinning frames stationary electromagnet sensors equipped with a permanent magnet which, depending on the rotation of the ring traveller or on the interruption of rotation of the same due to thread breakage, deliver signals to a surveying device. Obviously because of difficulties in the positioning in front of the spinning stations to be surveyed, it has however not been suggested to arrange such an electromagnetic surveying device on a carriage -moving cyclically past the spinning stations of a spinning machine, for example an automatic thread twisting connecting device.

It is the object of the present invention to avoid the disadvantages of the known devices and particularly to provide a surveying device of the above-mentioned type which, while reducing expense, assures reliable and disturbance-free operation.

According to the present invention, this problem is primarily solved by the combination of the following features:

For the indirect sensing of thread-breakage by surveying traveller rotation, there is provided on the carriage an electromagnetic thread sensor on the level of the traveller or respectively of the ring carrying the traveller which, for activating the stop device upon thread breakage, is connected with the latter;

The thread sensor is provided with a switching device for activating the sensor function;

On the carriage, there is provided a position sensor i for determining the actual relative position of the thread sensor with respect to the traveller or to the ring 'of each spinning station;

The use of the electromagnet thread sensor according to the present invention assures especially, because of the relatively wide influence zone of at least several millimeters of the rotating traveller of each station, reliable sensing of thread breakage. It is possible in this way to reduce the circuitry expenditure of the surveying device as well as the requirements as to precision of the position senser in a most simple way.

It is then especially advantageous if the position sensor is provided in the form of an electromagnetic sensor, since then both sensors can be adjusted to each other as far as sensitivity and influence width are concerned.

The invention can be realized in a particularly simple manner if the thread sensor comprises an induction coil, if a sensor coil is arranged in the field of the induction coil and if the induction coil and the sensor coil upon passage past a spinning station are placed so close to the movement path of the traveller that the field of the induction coil can be modulated by the rotating traveller. It is especially the use of an induction coil instead of the permanent magnet provided in the known systems which makes possible in a most simple manner adjusting of the transmitted signals and adaptation to various operating conditions. Furthermore, the switching on and off of the surveying device is effected in'a simple manner by switching on or respectively off of the direct current by the induction coil. It is then particularly advantageous if, in order to avoid magnetization of the traveller and/or of the ring, a switching device is provided which disconnects the current through the induction coil as soon as the same remains stationary in front of a traveller for a predetermined period of time.

The safety of operation of the surveying device can be furthermore improved if, between the sensor coil and the stop device for the carriage, there is provided at least one filter for filtering and for transmitting the signals induced by the traveller. Since the frequency of the traveller is already known, it is possible by accordingly tuning the filter to filter out exactly the frequency produced by the traveller and to transmit it to the stopping device for further evaluation whereas other signals, such, as for example, the impulses produced by carriage movement, can be retained.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciatethat the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structure for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of the invention.

A specific embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanyingdrawings, forming a part of the specification, wherein:

FIG. 1 shows schematically the arrangement of the bobbins of a ring spinning machine,

FIG. 2 shows a top elevation of the arrangement according to FIG. 1, but with a carriage for receiving an automatic thread twisting connecting device,

FIG. 3 shows a sensor with the features of the present invention at an enlarged scale,

FIG. 4 shows the block circuit scheme of a surveying device of the present invention, and

FIG. 5 shows the circuit arrangement for feeding the sensor according to FIG. 3.

As shown in section in FIGS. 1 and 2 bobbins 1 are arranged on the frame 2 of a ring spinning machine and are supplied with yarn by a stretching device (not shown) via travellers 3. In this instance, each traveller 3 rotates on the ring 5 of a ring bank 6 associated therewith. For surveying the individual bobbins to detect thread breakage, in a carriage 7 moving in parallel direction with the ring bank 6, which comprises twisting connection devices (not shown) for automatically starting operation of a spinning station deactivated by thread breakage, there is provided an electromagnetic thread sensor 8 which surveys the rotation of traveller 3 and therefore also the readiness for operation of the individual stations. On the carriage, beside the thread sensor 8, there is provided a position sensor 9 which determines by surveying marks 10 on the frame 2 if, in operation, the thread sensor 8 is situated immediately adjacent one of the rings 5. The position sensor 9 is, just as the thread sensor 8, provided in the form of an electromagnetic system, but in certain application fields, also other, for example mechanical or electrooptical, arrangements are possible for the position sensor 9. If the surveying device only serves for indicating thread breakage or for counting thread breakages, it may of course be placed on a separate carriage without a thread twisting connecting device.

As shown in FIG. 3, the thread sensor 8 comprises an induction coil 11 which is arranged above a sensor coil 12 on an iron core 13 common to both coils. The induction coil is in this case thus fed with direct voltage such that upon passage of the core 13 past a rotating traveller 3, the field of coil 11 is modulated and thereby voltage is induced in the sensor coil 12. As soon as, on one of the surveyed stations, the traveller 3 is immobilized because of thread breakage, no voltage at all is induced in the sensor coil by the field of the induction coil 11 so that the lack of a signal permits the conclusion that there is thread breakage.

The course of operation of the surveying device can be seen from the block circuit scheme according to FIG. 4. At first, upon approach to a spinning station to be surveyed, a circuit arrangement 14 for switching on the thread sensor is actuated by position sensor 9. At the same time, the stopping device 16 is fed with a stop signal via a switching conductor 15. The thread sensor 8, however, upon approach to one of the rotating travellers 3, also delivers a signal to the stop device 16 via filter 17, whereby the stop device 16 continues to supply the motor 18 for driving the carriage with voltage so that the carriage is moved on to the next bobbin. If however, in case of thread breakage, no signal is received by thread sensor 8, interruption of the voltage supply of motor 18 is effected because in this case the stop device 16 is only fed by position sensor 9, so that the carriage 7 is stopped in front of the station concerned and the thread connecting device can be started.

The filter 17 is constructed so that the thread sensor 8 only delivers to the stopping device 16 signals with a frequency corresponding to the rotation of the traveller and so that disturbing signals are suppressed in a most simple manner.

Since the induction coil 11 (FIG. 3) of the thread sensor 8 is fed with direct current, there is a danger that, if the carriage is stopped in front of a station for a longer period of time, the traveller 3 or the ring 5 is magnetized whereby the signals received by the thread sensor would be modified. On the position sensor, therefore, there is provided a disconnecting device 19 which is actuated by the position sensor 9 at the same time as the switching device 14 and again disconnects the switching device 14 and therefore also the thread sensor 8 after a predetermined period of time. Instead of the time function of the switching-off step, it is of course also possible to connect the switching-off device 19 for example with the stopping device 16 and to disconnect the thread sensor 8 at the same time as the carriage 7 is immobilized.

FIG. 5 shows in detail the circuit of the thread sensor 8 as well as of the filter 17. For voltage supply, in this case there is provided a direct current source 20 which is connected with the induction coil 11 via collector resistance 21 of a transistor 22. A control input 23 is thus connected via base resistance 24 with the base of transistor 22 that corresponding control signals, for example produced by position sensor 9 or by switching-off device 19, makes it possible to control the current flow through induction coil 11. Thereby, by corresponding dimensions of the resistances 21, 24 or by application of a separately produced base bias voltage, the current flow can be controlled in intensity by the induction coil 11 so that also adaptation of the surveying device to different types of travellers 3 or to varying distances between the thread sensor 8 and the traveller 3 (FIG. 2) is rendered possible.

As shown in FIG. 5, the high pass filter 17 comprises two condensers 25, 26 as well as a resistance 27. The filter is then given such dimensions that the high frequency signals produced by a rotating traveller are transmitted to an amplifier 28 and distrubing voltages of low frequency are short-circuited.

I believe that the construction and operation of my novel apparatus and process will now be understood, and that the advantages of my invention will be fully aprreciated by those persons skilled in the art.

I claim:

1. For surveying thread breakage in a spinning machine having a plurality of spinning stations each having a rotatable traveller the rotation of which is interrupted upon thread breakage, carriage means for cyclically moving along the individual spinning stations; signal responsive stop means for stopping said carriage; activatable electromagnetic sensor means carried by said carriage for, when activated, electromagnetically surveying traveller rotation sequentially at each station and passing a stop signal to said stop means upon detection of thread breakage as electromagnetically sensed from the condition of a traveller; switch means for activating said electromagnetic sensor means; position sen-,

sor means carried by said carriage for determining the actual position of said electromagnetic sensor means with respect to the traveller of each spinning station and for controlling said switch means to activate said thread sensor during each passage past the traveller of a spinning station.

2. Apparatus as claimed in claim 1 wherein said electromagnetic sensor means comprises an induction coil connectable with a direct current source through said switch means, and a sensor coil arranged in the field of said induction coil, said coils being arranged on said carriage means such that, upon passage past a spinning station, the field of the induction coil will be altematingly modulated by the rotating traveller of the spinning station, the sensor coil being connected to said stop means for passing thereto the resulting signal induced in said sensor coil.

3. Apparatus as claimed in claim 2 further comprising filter means between said sensor coil and said stopping means for delivering to said stopping means only signals of predetermined chacteristics related to the rotation of said traveller.

4. Apparatus as claimed in claim 2 further comprising disconnecting means for automatically interrupting current flow through said induction coil after said switch means has been closed for a predetermined time, so as to prevent magnetization of the traveller of a spinning station at which said carriage means may be stopped.

5. Apparatus as claimed in claim 4 wherein said switch means comprises a transistor controlled by said position sensor means and said disconnecting means.

6. Apparatus as claimed in claim 2 wherein said position sensor means is an electromagnetic sensor.

7. Apparatus as claimed in claim 1 wherein said position sensor means is connected to said stop means for passing a stop signal thereto and is operatively connected to said switch means for activating said electromagnetic sensor means during each passage past a spinning station, and wherein said electromagnetic sensor means is operatively connected to said stop means for passing thereto a non-stop signal to prevent activation of said stop means upon sensing normal traveller rotation. 

1. For surveying thread breakage in a spinning machine having a plurality of spinning stations each having a rotatable traveller the rotation of which is interrupted upon thread breakage, carriage means for cyclically moving along the individual spinning stations; signal responsive stop means for stopping said carriage; activatable electromagnetic sensor means carried by said carriage for, when activated, electromagnetically surveying traveller rotation sequentially at each station and passing a stop signal to said stop means upon detection of thread breakage as electromagnetically sensed from the condition of a traveller; switch means for activating said electromagnetic sensor means; position sensor means carried by said carriage for determining the actual position of said electromagnetic sensor means with respect to the traveller of each spinning station and for controlling said switch means to activate said thread sensor during each passage past the traveller of a spinning station.
 2. Apparatus as claimed in claim 1 wherein said electromagnetic sensor means comprises an induction coil connectable with a direct current source through said switch means, and a sensor coil arranged in the field of said induction coil, said coils being arranged on said carriage means such that, upon passage past a spinning station, the field of the induction coil will be alternatingly modulated by the rotating traveller of the spinning station, the sensor coil being connected to said stop means for passing thereto the resulting signal induced in said sensor coil.
 3. Apparatus as claimed in claim 2 further comprising filter means between said sensor coil and said stopping means for delivering to said stopping means only signals of predetermined chacteristics related to the rotation of said traveller.
 4. Apparatus as claimed in claim 2 further comprising disconnecting means for automatically interrupting current flow through said induction coil after said switch means has been closed for a predetermined time, so as to prevent magnetization of the traveller of a spinning station at which said carriage means may be stopped.
 5. Apparatus as claimed in claim 4 wherein said switch means comprises a transistor controlled by said position sensor means and said disconnecting means.
 6. Apparatus as claimed in claim 2 wherein said position sensor means is an electromagnetic sensor.
 7. Apparatus as claimed in claim 1 wherein said position sensor means is connected to said stop means for passing a stop signal thereto and is operatively connected to said switch means for activating said electRomagnetic sensor means during each passage past a spinning station, and wherein said electromagnetic sensor means is operatively connected to said stop means for passing thereto a non-stop signal to prevent activation of said stop means upon sensing normal traveller rotation. 